دانلود مقاله با موضوع بررسی طیفسنجی NMR رنگهای بنزوتیازولیل استونیتریل آزو
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موضوع به انگلیسی:NMR spectroscopic investigation of benzothiazolylacetonitrile azo dyes: CR7
substitution effect and semiempirical study
بخشی از متن:
Ebead et al. had reported in the synthesis and the UV–Visible solvatochromism combined with semiempirical
calculations to study the tautomerism of 1,3‐benzothiazol‐2‐ylacetonitrile azo dyes [1]. In this study, 1,3‐ben
zothiazol‐2‐ylacetonitrile azo dyes (1–6) have been resynthesized, one and two dimensional 1H and 13C NMR,
as well as absorption and emission spectra, were collected and interpreted. The obtained results were used to
clarify the tautomerization phenomenon of these dyes. Predominantly, these dyes exist in Z‐hydrazone form
reinforced through intramolecular hydrogen bonding in deuterated chloroform. Substituents (R) in carbon7
(CR7) are the key player of the changes in 1H and 13C NMR chemical shifts, also in the absorption and emission
wavelengths of benzothiazole azo dyes. Also, the relative photoluminescence quantum yields (PL QY) of these
dyes (1–6) were estimated and related to the nature of substituents. Finally, PM6 semiempirical calculations
were employed to confirm the preferred geometric structure and experimental NMR, absorption, and emission
results
